1. Field of the Invention
The present invention relates generally to a fast idle device for a carburetor, and more specifically to a fast idle device provided with a calculating circuit to electromagnetically control an optimum engine revolution speed when the engine is started or being warmed up.
2. Description of the Prior Art
Generally, a conventional carburetor is provided with a fast idle mechanism to produce an optimum engine idling speed according to the engine temperature when the engine is started or being warmed up. However, since the conventional mechanism comprises a cam and a lever, the engagement force therebetween increases with increasing engine temperature (explained in more detail hereinafter), thereby preventing the cam from rotating smoothly. This is because the initial load from the accelerator pedal is designed to be great and it therefore becomes necessary to depress the accelerator pedal deeply.
In addition, since automotive vehicles are usually used under diverse and severe operating conditions, that is, within a wide range of ambient temperature range from bitter cold to intense heat, there have been various problems in the use of a single fast idle cam in that a single cam cannot facilitate starting under all conditions, and may have the engine speed to become too high after starting. In addition, it is very difficult to determine an optimum cam profile which is suitable for the various conditions to be encountered.